The organizers of the $30 million Google Lunar X Prize say their contestants will abide by NASA's appeal to stay away from the Apollo landing sites and other places where U.S. moon probes ended up.

Last week, NASA laid down its guidelines for private moon missions, with an eye toward preserving sites such as the place where Apollo 11 commander Neil Armstrong took "one small step" onto the lunar surface in 1969. Space agency officials were worried that visiting spacecraft could ruin the sites, or try to salvage some of the historic hardware, or kick up moondust to obscure the tracks that have lasted for four decades.

The X Prize program is offering a multimillion-dollar payoff for the first team to land on the moon, take a 500-meter trek and send back high-definition images. It's also offering bonuses for taking pictures of an Apollo landing site or other "Lunar Heritage" site. But the X Prize organizers promise to take NASA's rules into account when approving the mission plans for the 26 teams vying for the prize. That means an X Prize team won't be allowed to land within 2 kilometers (1.2 miles) of the Apollo 11 site, or send a rover any closer than 75 meters (246 feet).

One of the teams, Pittsburgh-based Astrobotic Technology, had planned to take a close look at Apollo 11's artifacts and footprints, but President John Thornton said the venture has shifted its primary target to the lunar north pole. "The most exciting and most meaningful thing for mankind to do on the moon is to find water ice at the pole," he told me today. Astrobotic is aiming to launch its Icebreaker mission on a SpaceX Falcon 9 rocket in October 2015. Because no NASA probes ever landed or crashed in the area, the venture won't have to worry about the guidelines, at least for its first lunar mission.

Although NASA's lunar hardware is off-limits, Thornton said there's a "wild card" in the deck for potential moon targets. NASA's rules don't say anything about avoiding non-NASA probes, such as the Soviet Luna landers and Lunokhod rovers. In fact, at one time Astrobotic was talking with the current owner of Lunokhod 2, video-game developer and millionaire spaceflier Richard Garriott, about making an up-close inspection of the rover he bought from the Russians in 1993.